Will the person I'm following in Twitter will read the tweet I sent to him?

[Chrysanthemum]

I'm just following him and he's not following me. I actually sent a tweet on him by writing on the "what's on your mind" box:
@[username]: Hi there....

Will he be able to read it and be able to reply back?Thanks.

[Seleya]

Yes, he will see your tweet checking in his "@Mentions" tab on his profile.

He will not see it only if you set your account private, because in this case only your followers can see your tweets.